Examples of known molding systems are (amongst others): (i) the HyPET (trademark) Molding System, (ii) the Quadloc (Trademark) Molding System, (iii) the Hylectric (trademark) Molding System, and (iv) the HyMET (trademark) Molding System, all manufactured by Husky Injection Molding Systems (Location: Canada; www.husky.ca).
U.S. Pat. No. 3,767,339 (Inventor: HUNKAR; Published: 1973-10) discloses an injection molding control that provides for programmable control of ram velocity as a function of the position of the ram through closed-loop feedback of the measured actual velocity. Closed-loop feedback of the actual mold cavity pressure overrides the velocity program in an analog fashion to stop the ram when critical cavity pressure has been attained. A variable length ram stroke provides optimization of the shot size through automatic variation in response to the closed-loop feedback of ram position at the instant of the attaining of critical pressure in the previous injection cycle. The shot size control is used to maintain a constant cushion in each cycle as measured at the instant critical pressure is reached to insure constant product density and uniformity of shrinkage. Automatic recompensation of the velocity program domain with respect to ram position relates the material injection rate more directly to the actual quantity material being injected. Adaptation to factors such as material density and viscosity changes is realized.
U.S. Pat. No. 3,860,801 (Inventor: HUNKAR; Published: 1975-01) discloses an injection molding control to promote uniformity in the mass of the injection charge from cycle to cycle. An injection ram is reciprocated between a fixed forward, or cushion, point coincident with the end of charge injection, and an adjustable rearward, or retraction, point correlated to size of the next charge. The retraction point is corrected at the conclusion of each injection cycle in response to comparing a reference pressure, which is correlated to the mold cavity pressure existing at the conclusion of injecting a charge of the desired mass into the molding cavity, with the pressure of the plasticized material upstream of the orifice through which the material is injected into the mold cavity. The material pressure upstream of the orifice is sampled for comparison against the reference pressure at a point in time following injection when the ram has a predetermined velocity, preferably when it has come to rest, and the injected material in the region of the orifice has not yet solidified, whereby the sampled melt pressure is correlated to the cavity pressure at the conclusion of injection and hence to the mass of the injection charge. Depending upon whether the sampled melt pressure upstream of the orifice is above or below the reference pressure, the retraction point is shifted closer to, or further from, the orifice, respectively, to shorten or extend, respectively, the distance over which plasticized material for the next charge is accumulated forward of the ram tip.
U.S. Pat. No. 3,889,849 (Inventor: CHANDLER; Published: 1975-06) discloses a simplified process computer for effecting the continued operation of an injection molding machine in a predetermined mode. A timer is started when the injection ram begins an injection stroke. When a first predetermined time has elapsed, it is assumed that the initial cushion point has been reached and the ram injection pressure is reduced to a holding value. At a subsequent time a comparison is made between a signal representing an actual final ram cushion point position, and another signal representing the desired position. An error signal is then generated and utilized to change the screw-back and pull-back positions of the ram. Simultaneous modification of the screw-back and pull-back points maintains a constant shot volume for each injection stroke. In another embodiment the transition from injection to holding pressure is accomplished as a function of ram position rather than time. The error signal is then also utilized to control the point at which the pressure change occurs.
U.S. Pat. No. 3,941,534 (Inventor: HUNKAR; Published: 1976-03) discloses an injection molding control that provides for programmable control of ram velocity as a function of the position of the ram through closed-loop feed-back of the measured actual velocity. Closed-loop feed-back of the actual mold cavity pressure overrides the velocity program in an analog fashion to stop the ram when a preset cavity pressure has been attained associated with a desired charge size. Programmable control of the ram screw speed and/or back pressure during injection as a function of ram position or time is used to impart a predetermined temperature profile to the charge along the length thereof while it is in the barrel prior to injection. This enables controlled variation in density of the molded article throughout its volume to achieve desired levels in pre-selected characteristics such as surface wear, gloss, resolution and the like. A closed-loop servo system responsive to hydraulic pressure on the ram, including a flow divider valve which meters flow between the ram pressure chamber and a drain tank, provides accurate and continuous control of injection, hold and back pressure to enhance product quality; smooth pressure transitions between different ram pressure levels utilized in the molding cycle to avoid undesirable effects due to ram overshoot; simultaneous flow and pressure increase during injection when ram velocity falls below programmed level thereby avoiding sluggish response characteristics when restoring ram velocity; and reduction in number of hydraulic components required to effect the injection, hold, and back pressure functions.
U.S. Pat. No. 4,311,446 (Inventor: HOLD et al.; Published: 1982-01) discloses a method and an apparatus for controlling the parameters of injection molding processes in a machine having a barrel with a plasticating chamber and a screw, rotatably and slidably disposed in said chamber, hopper means adjacent one end of said chamber communicating therewith and nozzle means disposed in the other end of said chamber communicating with a mold. Control of the injection molding process is achieved through an event recognition philosophy by sensing screw position, screw injection velocity, melt temperature, comparing the values at certain instances during the work cycle with known or desired values and using these values, changes of values and differences of values to monitor and initiate changes in the process parameters.
U.S. Pat. No. 5,062,784 (Inventor: INABA et al.; Published: 1991-11) discloses a molding condition recording apparatus having a manual data input device with a CRT. The manual data input device has various keys for inputting parameters of various groups used for controlling injection, hold, metering and cylinder temperature, and for inputting molding defect indication data. A microprocessor for a programmable machine computer causes the input parameters and the molding defect indication data to be stored in a molding condition storage region of a shared memory. The microprocessor then discriminates similarity between the thus stored molding condition and the molding condition already registered in a molding condition/molding defect storage file of a memory other than the shared memory. If there is similarity between these molding conditions, the microprocessor causes the CRT to display an alarm message thereon together with the parameter already registered in the file and the mold defect indication data. When there is no similarity between the molding conditions, the microprocessor transfers the molding condition stored in the shared memory to the file for storage therein. Even when the alarm message is displayed, a similar transfer and storage process is carried out if it is requested by an operator.
U.S. Pat. No. 5,035,598 (Inventor: FUJITA et al; Published: Jul. 30, 1991) discloses an optimum molding condition setting system for an injection molding machine comprises a molten material flow analysis component for analyzing resin flow, resin cooling and the structure/strength of molded products by using a designed mold model and also comprises an analysis result evaluation component for determining an initial molding condition and its permissible range in accordance with the analysis results. The initial molding condition is set into the injection molding machine and a test shot is carried out in order to check for a deficiency of a molded product. If a deficiency of the molded product is detected, a data of the deficiency is entered into a molding defect elimination component. After performing a convenient data processing based on the entered data, a cause of the molding defect can be inferred and a measure for the cause can be obtained with high efficiency and accuracy. Consequently, the molding condition can properly and immediately be corrected in accordance with data obtained by the molten material flow analysis component.
U.S. Pat. No. 5,470,218 (Inventor: HILLMAN et al.; Published: 1995-11) discloses an injection blow molding apparatus. The apparatus includes an injection blow molding machine having work stations and molds. The apparatus includes a process computer for operating the blow molding machine according to a set of processing parameters. Each processing parameter has a respective desired operating range. The apparatus includes a touch screen for inputting signals to the processor for commanding the process computer to adjust the processing parameters. Display software and hardware coupled to the process computer and the touch screen cause the monitor to display respective icons representing each processing parameter. The value of each respective processing parameter is displayed adjacent to the icon. Graphing software generates signals which are transmitted to the monitor. The monitor displays a graph of the selected processing parameter value as a function of time. The graph is plotted in response to an operator touching a portion of the touch screen beneath which the selected icon is displayed. Alarm software causes the monitor to display an alarm message. The alarm message identifies whether any one of the processing parameters is operating outside its desired operating range.
U.S. Pat. No. 5,500,166 (Inventor: SASAKI et al.; Published: 1996-03) discloses an injection and compression molding process where molten material is fed by a screw, incorporating a counter-flow preventing valve (CPV), through a flow control valve (FCV) into a mold cavity. The injection volume is controlled by/with the FCV closed. The process includes: (I) feeding a predetermined quantity of material through the CPV into a chamber between the CPV and the FCV, then (II) advancing the screw with the FCV maintained closed to cause the CPV to close, thereby raising the pressure of the material in the chamber, determining when the pressure of the material in the chamber reaches a predetermined pressure, (III) determining whether the movable die is at a predetermined distance from the stationary die, (IV) opening the FCV after the pressure of the material in the chamber has reached said predetermined pressure and the movable die is at the predetermined distance from the stationary die, (V) setting as an original point of a determination of the injection volume either (a) a position of the screw at the opening of the FCV or (b) a time at the opening of the FCV, (VI) injecting the material into the mold cavity while the mold cavity is open to atmospheric pressure, closing the FCV either (a) when the screw has reached a position advanced a predetermined distance from the thus set original point or (b) at a predetermined time after the thus set original point, and compressing the material in the mold cavity.
U.S. Pat. No. 5,518,671 (Inventor: TAKIZAWA et al.; Published: 1996-05) discloses a method of setting molding conditions for an injection molding machine 1 using a mold 2 whose specifications data are unclear included three setting processes. In the first setting process A, by inputting known data into computer 3, the molding conditions based on a data base prepared in advance and said input known data are set. In the second setting process B, injection molding is performed according to prescribed molding conditions pre-selected concerning injection pressure P, injection speed V and the injection start position of screw 4, and then, based on the product just molded, injection pressure P is altered, to set said altered injection pressure P, injection speed V and proper pre-feed measurement value Md as molding conditions. In the third setting process C, injection molding is performed according to molding conditions obtained from said second setting process B, and subsequently, taking into account the findings from the product just molded, said molding conditions are adjusted. In this manner, even an unskilled operator is allowed to undertake setting molding conditions reliably and with great ease for an injection molding machine loaded with a set of molds whose specifications data are unclear.
U.S. Pat. No. 5,539,650 (Inventor: HEHL; Published; Jul. 23, 1996) discloses computer based interactive control of a plastics injection molding machine during input of portions of a production sequence and configuration of an injection cycle, which is effected essentially before the onset of the injection molding process. For a mold guided by an operator, operating parameters required for a process sequence are input by way of an input unit into a computer based control unit storing these operating parameters. Subsequently, one or a plurality of injection cycles is implemented according to the stored operating parameters. A physically possible production sequence, as well as a production sequence that is structurally specific to the machine and the tool employed, including any peripheral devices provided at the respective machine or associated therewith, are determined with the control unit. An operator is provided with a selection of possible inputs of further portions of the production sequence that can be added to the existing portions and are compatible with the machine and the tool based on the determination.
U.S. Pat. No. 5,550,744 (inventor: STEINBICHLER; Published: Aug. 27, 1996) discloses a process for controlling a production machine, in particular an injection molded machine that produces injection molded plastic parts. During a learning cycle, rating fields that indicate the relationship between selected quality parameters of the products and selected setting parameters of the machine are determined and stored. To allow the machine to be controlled by entering the actual target values, i.e. the quality parameters of the products, the set values or set value ranges for at least two selected quality parameters are entered into a control device. The control device then determines at least one set of selected setting parameters on the basis of the stored rating fields, all predetermined quality parameters simultaneously corresponding to the predetermined set values or lying in the predetermine set value ranges.
U.S. Pat. No. 5,898,591 (Inventor: HETTINGA et al.; Published: 1999-04) discloses an article of manufacture is provided where the article of manufacture comprises a computer usable medium having computer readable program code means therein. The computer readable program code means causes a computer to receive information, establish a molding profile based on the information, operate a molding machine to mold an article according to the molding profile, receive additional information corresponding to detected irregularities on the molded article, establish a modified molding profile based on the additional information received, and operate the molding machine to mold an additional article according to the modified molding profile. The additional information received by the computer which corresponds to detected irregularities on the molded article may be provided by a human operator, by a second computer, or by any other means.
U.S. Pat. No. 5,900,259 (Inventor: MIYOSHI et al.; Published: 1999-05) discloses a molding condition optimizing system for an injection molding machine comprising plastic flow condition optimizing section and an operating condition determining section is disclosed. The plastic flow condition optimizing section carries out a plastic flow analysis on a molded part model, and determines an optimum flow condition in a filling stage and a packing stage of an injection molding process of the injection molding machine by repeatedly executing an automated calculation using the result of the plastic flow analysis and the plastic flow analysis itself. The operating condition determining section comprises an injection-side condition determining section for determining an optimum injection-side condition of the injection molding machine according to the optimum flow condition obtained by the plastic flow condition optimizing means and a knowledge database with respect to an injection condition, and a clamping-side condition determining section for determining an optimum clamping-side condition according to the molded part form data generated by the plastic flow condition optimizing means, the result of the plastic flow analysis, mold design data, and a knowledge database with respect to a mold clamping condition.
U.S. Pat. No. 7,037,452 (Inventor: SPEIGHT; Published: May 2, 2006) discloses a method for the automated optimization of an injection molding machine set-up process comprising injection molding one or more parts, inspecting the parts for defects, adjusting the injection stroke and/or the injection velocity and repeating the process until the defects are reduced. There is also disclosed a method comprising injection molding one or more parts, determining a mean injection pressure profile by measuring the injection pressure with the machine configured with a constant, desired injection velocity. Then the velocity profile is adjusted to reduce differences between the measured pressure and the mean pressure profile. A further method is disclosed wherein the kickback is calculated and adjusted from screw displacement, packing/holding time and pressure. Also disclosed is a method comprising injection molding one or more parts then determining the gate freeze time by incrementing the holding time and measuring the screw displacement.
United States Patent Application Number 2001/0051858 (Inventor: LIANG et al; Published: Dec. 13, 2001) discloses a combination of an experimental design method with a mold-flow analysis software to simulate the real injection molding processes of the injection molding machine, analyze the simulation results, and develop a database for the quantitative relationship between the parameters of the injection molding machine and the parameters of the injection molding product quality. The database is then used to develop a neural network which can predict the qualities of the injection molding products. The operators of the injection molding machine can input the undetermined parameters to the developed neural network; after execution, the neural network outputs the predicted parameters of the injection molding product quality. The present invention can help the operators to set the parameters, cut down the time on finding appropriate molding parameters, reduce the time of futile try-and-error, and enhance quality by reducing defects.
United States Patent Application Number 2004/093115 (Inventor: USUI et al; Published: May, 13, 2004) discloses the following: when a determination condition is set for determining whether a molded product is non-defective or defective, a molding operation is performed a predetermined number of times. In each molding operation, an actual value of at least one monitor item which can serve as the basis for determining whether a molded product is non-defective or defective is detected. The detected actual values are displayed on a screen of a display in such a manner that a distribution of the actual values can be visually grasped. A sampling zone for the displayed actual values is designated in such a manner that a portion of the displayed actual values are contained in the sampling zone. The determination condition is automatically set on the basis of actual values contained in the sampling zone.
Non-patent publication titled: “Artificial Intelligence Already Taking Many Forms in Plastics Processing” authored by Matthew H. NAITOVE (this article is believed to be published in a trade journal called “Plastics Technology”) discloses software smart machines and smart factories are coming to plastics processing.
Non-patent publication titled: “Intelligent Molding: Expert Systems Are Coming On Line Now” authored by Jack K. ROGERS (this article is believed to be published in a trade journal called “Modern Plastics International” in May 1992 from pages 44 to 47) discloses that processing engineers are applying expert system technology to injection molding, replacing the “black art” of experienced machine operators who instinctively knows which knob to tweak with a computer program.
Non-patent publication titled: “Controls That Think bring Improved Accuracy to Injection Molding” authored by Joseph A. SNELLER (this article is believed to be published in a trade journal called “Modern Plastics” in December 1985 from pages 42 to 44) discloses that every one is foolproof molding. Now process controls that analyze what's happening in the machine and apply human-like reasoning to the problem could make bad-part rejects a thing of the past.
Non-patent publication titled: “Adaptive Process Control for Injection Molding” authored by R. NUNN and C. GROLMAN (this article is believed to be published in a trade journal called “ANTEC '88” from pages 298 to 304) discloses that in practice, the molder knows that the successful application of the process is critically dependent on a very elusive complex of interrelated dimensions; mass, time, pressure, and temperature.
Non-patent publication titled: “Sophisticated New Computer Systems Analyze Injection Molding” and the author is unknown (this article is believed to be published in a trade journal called “Plastics Technology” in November 1985 from pages 29 and 31) discloses that computers have been developed for plastics injection molding process analysis, such as: (i) searching for an optimum processing conditions for a given resin or compound, and (ii) implying troubleshooting of molding problems.